Question 1

Question 1Draw the branched structural formula of the following organic compounds whose IUPAC names are given below.Pent-1-eneBut-2-yne3-methyl pentane2-methyl-prop-1-enePentan-3-ol1, 1, 2, 2 tetrabromoethane2-methyl butan-2-ol2, 2 dimethylpropan-1-ol2, 2 dimethyl propane2-bromo-4-chloro pentane

Accepted Answer

Pent-1-eneBut-2-yne3-methyl pentane2-methyl-prop-1-enePentan-3-ol1, 1, 2, 2 tetrabromoethane2-methyl butan-2-ol2, 2 dimethylpropan-1-ol2, 2 dimethyl propane2-bromo-4-chloro pentane

Question 2

Question 2Select the correct answer from the choice in brackets.The vapour density of the fifth member of the homologous series of alkanes. [22/36/29]The isomer of pentane which has '1' C atom attached to '4' other C atoms [n-/iso-/neo-] pentane.The IUPAC name of the product of reaction of ethylene with hydrogen bromide, [ethyl bromide/bromoethane/dibromoethane]The IUPAC name of methyl acetylene. [1-butyne/propyne/ethyne]The functional group in ethanoic acid. [aldehydic/carboxyl/hydroxyl]

Accepted Answer

36neo-pentanebromoethanepropynecarboxyl

Question 3

Question 3Give balanced equations for the following conversions:1,2 dibromoethane→AAcetylene→BSilver acetylide	ext{1,2 dibromoethane} \xrightarrow{	ext{A}} 	ext{Acetylene} \xrightarrow{	ext{B}} 	ext{Silver acetylide}1,2 dibromoethaneA​AcetyleneB​Silver acetylideEthanol→CEthene←DEthyl iodide	ext{Ethanol} \xrightarrow{	ext{C}} 	ext{Ethene} \xleftarrow{	ext{D}} 	ext{Ethyl iodide}EthanolC​EtheneD​Ethyl iodideBromoethane→EEthane←FSodium propanoate	ext{Bromoethane} \xrightarrow{	ext{E}} 	ext{Ethane} \xleftarrow{	ext{F}} 	ext{Sodium propanoate}BromoethaneE​EthaneF​Sodium propanoateSodium ethanoate→GMarsh gas→G1Methanol→G2Methanal→G3Methanoic acid	ext{Sodium ethanoate} \xrightarrow{	ext{G}} 	ext{Marsh gas} \xrightarrow{	ext{G}_1} 	ext{Methanol} \xrightarrow{	ext{G}_2} 	ext{Methanal} \xrightarrow{	ext{G}_3} 	ext{Methanoic acid}Sodium ethanoateG​Marsh gasG1​​MethanolG2​​MethanalG3​​Methanoic acidSodium acetate + H2←HAcetic acid→H1Ethyl ethanoate	ext{Sodium acetate + H}_2 \xleftarrow{	ext{H}} 	ext{Acetic acid} \xrightarrow{	ext{H}_1} 	ext{Ethyl ethanoate}Sodium acetate + H2​H​Acetic acidH1​​Ethyl ethanoate

Accepted Answer

1. 1,2 dibromoethane→AAcetylene	ext{1,2 dibromoethane} \xrightarrow{	ext{A}} 	ext{Acetylene}1,2 dibromoethaneA​AcetyleneAcetylene→BSilver acetylide	ext{Acetylene} \xrightarrow{	ext{B}} 	ext{Silver acetylide}AcetyleneB​Silver acetylideHC ≡ CH ethyne+2AgNO3+2NH4OH⟶Ag-C ≡ C-AgSilver Acetylide+2NH4NO3+2H2O\underset{	ext{ ethyne}}{	ext{HC ≡ CH}} + 2	ext{AgNO}_3 + 2	ext{NH}_4	ext{OH} \longrightarrow \underset{	ext{Silver Acetylide}}{	ext{Ag-C ≡ C-Ag}} + 2	ext{NH}_4	ext{NO}_3 + 2	ext{H}_2	ext{O} ethyneHC ≡ CH​+2AgNO3​+2NH4​OH⟶Silver AcetylideAg-C ≡ C-Ag​+2NH4​NO3​+2H2​O2. Ethanol→CEthene	ext{Ethanol} \xrightarrow{	ext{C}} 	ext{Ethene}EthanolC​EtheneC2H5OH ethyl alcohol→170°CConc. H2SO4[excess]C2H4ethene+H2O \underset{	ext{ ethyl alcohol}}{	ext{C}_2	ext{H}_5	ext{OH}} \xrightarrow[170\degree	ext{C}]{	ext{Conc. H}_2	ext{SO}_4	ext{[excess]}} \underset{ 	ext{ethene}}{	ext{C}_2	ext{H}_4} + 	ext{H}_2	ext{O}\ ethyl alcoholC2​H5​OH​Conc. H2​SO4​[excess]170°C​etheneC2​H4​​+H2​O Ethyl iodide→DEthene	ext{Ethyl iodide} \xrightarrow{	ext{D}} 	ext{Ethene}Ethyl iodideD​EtheneC2H5I ethyl iodide+KOH alcoholic→boilC2H4 ethene+KI+H2O\underset{	ext{ ethyl iodide}}{	ext{C}_2	ext{H}_5	ext{I}} + \underset{ 	ext{ alcoholic}}{	ext{KOH}} {\xrightarrow{	ext{boil}}} \underset{ 	ext{ ethene}}{	ext{C}_2	ext{H}_4} + 	ext{KI} +	ext{H}_2	ext{O} ethyl iodideC2​H5​I​+ alcoholicKOH​boil​ etheneC2​H4​​+KI+H2​O3. Bromoethane→EEthane	ext{Bromoethane} \xrightarrow{	ext{E}} 	ext{Ethane}BromoethaneE​EthaneC2H5Brbromoethane+2[H]nascent hydrogen→alcoholZn/Cu coupleC2H6ethane+HBr\underset{	ext{bromoethane}}{	ext{C}_2	ext{H}_5	ext{Br}} + \underset{	ext{nascent hydrogen}}{2	ext{[H]}} \xrightarrow[	ext{alcohol}]{	ext{Zn/Cu couple}} \underset{	ext{ethane}}{	ext{C}_2	ext{H}_6} +	ext{HBr}bromoethaneC2​H5​Br​+nascent hydrogen2[H]​Zn/Cu couplealcohol​ethaneC2​H6​​+HBrEthane←FSodium propanoate	ext{Ethane} \xleftarrow{	ext{F}} 	ext{Sodium propanoate}EthaneF​Sodium propanoateC2H5COONasodium propanoate+NaOHsodalime→300°CCaOC2H6↑ethane+Na2CO3\underset{	ext{sodium propanoate}}{	ext{C}_2	ext{H}_5	ext{COONa}} + \underset{	ext{sodalime}}{	ext{NaOH}} \xrightarrow[300\degree	ext{C}]{	ext{CaO}} \underset{	ext{ethane}}{	ext{C}_2	ext{H}_6 \uparrow} + 	ext{Na}_2	ext{CO}_3sodium propanoateC2​H5​COONa​+sodalimeNaOH​CaO300°C​ethaneC2​H6​↑​+Na2​CO3​4. Sodium ethanoate→GMarsh gas	ext{Sodium ethanoate} \xrightarrow{	ext{G}} 	ext{Marsh gas}Sodium ethanoateG​Marsh gasCH3COONa sodium acetate+NaOHsodalime→300°CCaOCH4↑methane+Na2CO3\underset{	ext{ sodium acetate}}{	ext{CH}_3	ext{COONa}} + \underset{	ext{sodalime}}{	ext{NaOH}} \xrightarrow[300\degree	ext{C}]{	ext{CaO}} \underset{	ext{methane}}{	ext{C}	ext{H}_4 \uparrow} + 	ext{Na}_2	ext{CO}_3 sodium acetateCH3​COONa​+sodalimeNaOH​CaO300°C​methaneCH4​↑​+Na2​CO3​Methane to Methanol to Methanal to Methanoic acidCH4 Methane→K2Cr2O7[O]CH3OHmethanol→K2Cr2O7[O]HCHOmethanal→K2Cr2O7[O]HCOOHmethanoic acid\underset{	ext{ Methane} }{	ext{CH}_4} \xrightarrow[	ext{K}_2	ext{Cr}_2	ext{O}_7]{	ext{[O]}} \underset{	ext{methanol}}{	ext{CH}_3	ext{OH}} \xrightarrow[	ext{K}_2	ext{Cr}_2	ext{O}_7]{	ext{[O]}} \underset{	ext {methanal}}{	ext{HCHO}} \xrightarrow[	ext{K}_2	ext{Cr}_2	ext{O}_7]{	ext{[O]}} \underset{	ext{methanoic acid}}{	ext{HCOOH}} MethaneCH4​​[O]K2​Cr2​O7​​methanolCH3​OH​[O]K2​Cr2​O7​​methanalHCHO​[O]K2​Cr2​O7​​methanoic acidHCOOH​5. Sodium acetate + H2←HAcetic acid	ext{Sodium acetate + H}_2 \xleftarrow{	ext{H}} 	ext{Acetic acid}Sodium acetate + H2​H​Acetic acid2CH3COOHAcetic acid+2Na⟶2CH3COONasodium acetate+H22\underset{	ext{Acetic acid}}{	ext{CH}_3	ext{COOH}} + 2	ext{Na} \longrightarrow \underset{	ext{sodium acetate}}{2	ext{CH}_3	ext{COONa}} + 	ext{H}_22Acetic acidCH3​COOH​+2Na⟶sodium acetate2CH3​COONa​+H2​Acetic acid→H1Ethyl ethanoate	ext{Acetic acid}\xrightarrow{	ext{H}_1} 	ext{Ethyl ethanoate}Acetic acidH1​​Ethyl ethanoateC2H5OHethyl alcohol+CH3COOHAcetic acid→Conc. H2SO4CH3−COO−C2H5ethyl ethanoate+H2O\underset{	ext{ethyl alcohol}}{	ext{C}_2	ext{H}_5	ext{OH}} + \underset{	ext{Acetic acid}}{	ext{CH}_3	ext{COOH}} \xrightarrow{	ext{Conc. H}_2	ext{SO}_4} \underset{	ext{ethyl ethanoate}}{	ext{CH}_3-	ext{COO}-	ext{C}_2	ext{H}_5} + 	ext{H}_2	ext{O}ethyl alcoholC2​H5​OH​+Acetic acidCH3​COOH​Conc. H2​SO4​​ethyl ethanoateCH3​−COO−C2​H5​​+H2​O

Question 4

Question 4Select from the letters A to G the correct answer corresponding to the statements from 1 to 5 :   A : Ammoniacal CuCl2   B : Trichloromethane   C : Trichloroethane   D : Bromine soln.   E : Aqueous KOH   F : Ethene   G : Sodalime   H : Ethanol   I : EthyneThe organic compound which forms carbon tetrachloride on reaction with chlorine.The reagent which can distinguish between ethene and ethyne.The substance which reacts with bromoethane to give ethanol.The substance which gives bromoethane on reaction with hydrogen bromide.The substance which reacts with acetic acid to give CH3COOC2H5AnswerThe organic compound which forms carbon tetrachloride on reaction with chlorine. — B : TrichloromethaneThe reagent which can distinguish between ethene and ethyne. — A : Ammoniacal CuCl2The substance which reacts with bromoethane to give ethanol. — E : Aqueous KOHThe substance which gives bromoethane on reaction with hydrogen bromide. — F : EtheneThe substance which reacts with acetic acid to give CH3COOC2H5 — H : Ethanol

Accepted Answer

Answer: B : Trichloromethane, A : Ammoniacal CuCl2, E : Aqueous KOH, F : Ethene, H : Ethanol

Question 5

Question 5Give balanced equations for the following conversions.An alkyne to an alkene.An alkene to an alkane.An alkane to an alcohol.An alcohol to an alkene.A carboxylic acid to an ammonium salt

Accepted Answer

1. An alkyne to an alkene:H2C2 ethyne [acetylene]+H2→300°CNickleC2H4ethene\underset{	ext{ ethyne [acetylene]}}{	ext{H}_2	ext{C}_2} + 	ext{H}_2 \xrightarrow[300\degree	ext{C}]{	ext{Nickle}} \underset{	ext{ethene}}{	ext{C}_2	ext{H}_4} ethyne [acetylene]H2​C2​​+H2​Nickle300°C​etheneC2​H4​​2. An alkene to an alkane:C2H4ethene+H2→300°CNickleC2H6ethane\underset{	ext{ethene}}{	ext{C}_2	ext{H}_4} + 	ext{H}_2 \xrightarrow[300\degree	ext{C}]{	ext{Nickle}} \underset{	ext{ethane}}{	ext{C}_2	ext{H}_6}etheneC2​H4​​+H2​Nickle300°C​ethaneC2​H6​​3. An alkane to an alcohol:2C2H6 ethane+O2→200°CCu tube2C2H5OHethanol\underset{	ext{ ethane}}{2	ext{C}_2	ext{H}_6} + 	ext{O}_2 \xrightarrow[200 	ext{\degree C}]{	ext{Cu tube}} \underset{	ext{ethanol}}{2	ext{C}_2	ext{H}_5	ext{OH}} ethane2C2​H6​​+O2​Cu tube200°C​ethanol2C2​H5​OH​4. An alcohol to an alkene:C2H5OH ethyl alcohol→170°CConc. H2SO4[excess]C2H4ethene+H2O \underset{	ext{ ethyl alcohol}}{	ext{C}_2	ext{H}_5	ext{OH}} \xrightarrow[170\degree	ext{C}]{	ext{Conc. H}_2	ext{SO}_4	ext{[excess]}} \underset{ 	ext{ethene}}{	ext{C}_2	ext{H}_4} + 	ext{H}_2	ext{O}\ ethyl alcoholC2​H5​OH​Conc. H2​SO4​[excess]170°C​etheneC2​H4​​+H2​O 5. A carboxylic acid to an ammonium salt :CH3COOH acetic acid+NH4OH⟶CH3COONH4Ammonium acetate+H2O \underset{	ext{ acetic acid}}{	ext{CH}_3	ext{COOH}} + 	ext{NH}_4	ext{OH}\longrightarrow \underset{ 	ext{Ammonium acetate}}{	ext{CH}_3	ext{COONH}_4} + 	ext{H}_2	ext{O}\ acetic acidCH3​COOH​+NH4​OH⟶Ammonium acetateCH3​COONH4​​+H2​O

Question 6

Question 6.1Give reasons for the following :Concentrated sulphuric acid may be added during esterification of acetic acid.

Accepted Answer

Reversible reaction may be prevented by using conc. H2SO4 when the reaction is about to complete by removing H2O.C2H5OHethyl alcohol+CH3COOHacetic acid→Conc. H2SO4CH3−COO−C2H5ethyl ethanoate+H2O\underset{	ext{ethyl alcohol}}{	ext{C}_2	ext{H}_5	ext{OH}} + \underset{	ext{acetic acid}}{	ext{CH}_3	ext{COOH}} \xrightarrow{	ext{Conc. H}_2	ext{SO}_4} \underset{	ext{ethyl ethanoate}}{	ext{CH}_3-	ext{COO}-	ext{C}_2	ext{H}_5} + 	ext{H}_2	ext{O}ethyl alcoholC2​H5​OH​+acetic acidCH3​COOH​Conc. H2​SO4​​ethyl ethanoateCH3​−COO−C2​H5​​+H2​O

Question 7

Question 6.2Give reasons for the following :Isomers belonging to the same homologous series may differ in physical properties but not in chemical properties.

Accepted Answer

As isomers have same general molecular formula and functional group (if any) and only differ in structural formula, hence, they show same chemical properties and differ in physical properties.

Question 8

Question 6.3Give reasons for the following :A given organic compound can be assigned only one name on the basis of the IUPAC system.

Accepted Answer

IUPAC is a systematic way of nomenclature of organic compounds that takes into account only one molecular structure of the compound. Hence, it assigns only one name to the compound.

Question 9

Question 6.4Give reasons for the following :Substitution reactions are characteristic reactions of saturated organic compounds only.

Accepted Answer

In saturated hydrocarbons, all the four valencies of each carbon are satisfied by the hydrogen atoms, forming single covalent bond. The non-availability of electrons in the single covalent bond makes them less reactive and therefore undergo characteristic substitution reaction only. Addition reactions are not possible in case of saturated organic compounds.

Question 10

Question 6.5Give reasons for the following :Acetic acid is considered an aliphatic monocarboxylic acid.

Accepted Answer

Acetic acid (CH3 – COOH) contains only one – COOH group (carboxylic acid group) that is why it is called a monocarboxylic acid. As acetic acid does not contain a benzene ring, so it is an aliphatic monocarboxylic acid.

Organic Chemistry - Unit Test Paper